The invention relates to a circuit arrangement for an electrical seat heater of a vehicle.
Known circuit arrangements for electrical seat heaters in vehicles have a heating element in the form of a heating resistor and a temperature-dependent sensor resistor which is connected to measuring electronics in order to determine the seat temperature. A circuit arrangement of this kind is disclosed in DE 198 11 823 B4. With this known circuit arrangement, the sensor resistor and the heating resistor are connected to the same ground potential in the region of the vehicle seat. The control unit, which is remote from the vehicle seat and which contains the measuring electronics, does not have a ground connection to the seat ground to which the sensor resistor and the heating resistor are connected. The control unit is connected to another ground which is remote from the vehicle seat. A so-called ground offset, which can easily lie in the range of +/−1 Volt, regularly occurs with ground connections which are remote from one another in this way. The measurement at the sensor resistor is falsified by this ground offset so that an exact determination of the temperature is not possible with the known circuit arrangement.